The key performance indicators for center ring are reliability and variability. We fabricate these Half Center Ring, SUS304 for FV and HV systems. These centering rings are used for mating ISO flanges and include both the centering ring and O-ring. The ISO flange (also called Large ISO) is used for FV and HV chamber ports and is available in three distinct styles: ISO-KF, ISO-K which uses clamp fasteners and ISO-F which uses nut and bolt fasteners.